Technical Noisy fan belt (?) trouble 1.2 8v

[Skotten84]

Hi,

Lucy, my beloved 1.2 8v '04 Punto, has a strange fan belt (?) problem.

A very loud, high pitched whirring noise comes from the driver's of the engine bay. But the thing is, it's VERY intermittent, seemingly not coupled to being cold or hot etc, it just happens very occasionally and randomly,. for like 5-10 seconds, then stops. Sometimes on start up, sometimes in the middle of a long journey, occasionally whilst parking....

A visual inspection of the belt itself shows no signs of wear and tear. It in fact looks to have been done, although I have no proof of this.

Question: is there anything else that commonly causes this on our beloved Puntos? Some kind of crankcase bearing or something?

Help greatly appreciated as always!

 

[Ziggy122]

Hi,

Lucy, my beloved 1.2 8v '04 Punto, has a strange fan belt (?) problem.

A very loud, high pitched whirring noise comes from the driver's of the engine bay. But the thing is, it's VERY intermittent, seemingly not coupled to being cold or hot etc, it just happens very occasionally and randomly,. for like 5-10 seconds, then stops. Sometimes on start up, sometimes in the middle of a long journey, occasionally whilst parking....

A visual inspection of the belt itself shows no signs of wear and tear. It in fact looks to have been done, although I have no proof of this.

Question: is there anything else that commonly causes this on our beloved Puntos? Some kind of crankcase bearing or something?

Help greatly appreciated as always!

If it was a crankcase bearing - you'd have serious issues

Its probably stretched a little bit since having a new belt put on
as a result its a little slack

A rotation of the alternator in the mounts to reapply tension will probably cure this

Unless there is contamination within the best itself, such as oil or anti-freeze

These belts dont hardly ever get replaced, mines at 85K and an original
Dont get me wrong, its crap, but still working
Whats worse that could happen? i loose my alternator, no biggie

Ziggy

 

[atom0007]

worst is it shreds the timing belt

 

[Brendan W]

worst is it shreds the timing belt

I have that particular tee shirt

 

[Skotten84]

If it was a crankcase bearing - you'd have serious issues

Its probably stretched a little bit since having a new belt put on
as a result its a little slack

A rotation of the alternator in the mounts to reapply tension will probably cure this

Unless there is contamination within the best itself, such as oil or anti-freeze

These belts dont hardly ever get replaced, mines at 85K and an original
Dont get me wrong, its crap, but still working
Whats worse that could happen? i loose my alternator, no biggie

Ziggy

Thanks for your reply!

Is it true that unlike many engines, if the belt goes on a 1.2 8v, the motor will simply stop and the top end won't be catastrophically damaged?

How does one go about rotating the alternator in it's mounts? The Haynes manual claims I need a special tool to set the tensioner correctly?

 

[flisko]

no need for special tool for alternator belt, just push alternator with one hand and tighten bolts with other hand so its nice and tight

 

[bluejohn125]

Take off the belt (or slacken it a lot) and then spin / push / pull all the rotating components it goes round. Feel for play or roughness. For example there is probably an idler pulley that could have a failing bearing, or even the alternator itself. I don't know the exact layout of the car, but you get the idea.

Usually a slack / old belt will squeal when you start up from cold with the lights on for example. For it to do it intermittently when driving, well something must move or be in operation I'd say. You are putting a load onto the system.

Don't forget it could be to do with the power steering... check the belt and fluid there. When idling, turn the steering lock to lock a few times and listen. Fluid can get old and contaminated, no-one generally replaces it.

For belt tension, they usually say it should take a half-twist in the middle between pulleys.

 

[inki]

Skotten84, check tension of belt,you don't have powersteering fluid it's electric & you are correct 1.2 8v engine is non interference no damage if the cambelt breaks.

 

[Brendan W]

If the alternator belt is not slack it could be the alternator bearings. Removing the belt and spinning the alternator could show it up.
It may not be related to the alternator at all. Standard advice for a noise at that end of the motor is to remove the alternator belt and see if the noise goes away. Clearly not so simple in this case because it's intermittent. The timing belt tensioner could be loose or failing or both. If it's loose it does give the odd squeal particularly when accelerating in lower gears from cold.

 

[jazz452]

Just change the belt and clean all the wheels incase of contamination, see how it goes.

 

[atom0007]

Diagnose it first , rather than throwing a belt at it. As suggested, loosen nuts (3) on alternator, rotate whole mount to remove tension from belt. Then re tension, but maybe not as tight, see if it goes away.

 

[jazz452]

And remember its the side of the belt that grips the wheels, if its thin replace it.